Last year a local guy sold a total rebuild and rotary mower with "over running clutch" and loader for $5,000.00. I have to admit, it was in great shape. The norm is $3,000 to $5,000, again depending on condition of tractor and what's tied to the back.
They are like old trucks, still get used.
"What is a weed? A plant whose virtues have not yet been discovered."
Ralph Waldo Emerson (1803-1882)